The New York-based doctor booking service today announced plans to launch across the US after surpassing 5 million users last month. Previously, ZocDoc’s booking functionality was only available in 2,000 cities and towns — 40% of the US market. Until today, the company kept geographical restrictions in place as it launched periodically in major cites and regions.

By the end of 2014, ZocDoc shares that it will be available everywhere in the contiguous United States. With its national expansion plans public, CEO Cyrus Massoumi made his confidence in the company’s mission crystal clear:

“Early in ZocDoc’s life, many people said our service would never work outside of New York City. We’ve now successfully launched ZocDoc in big cities, suburbs, and rural areas throughout the country, and I’m proud to say that our service works regardless of geography or type of practice.”

Beyond the US

Massoumi tells us he’s hyper-focused on the US but that an international launch wouldn’t be impossible: “We know that there’s demand for ZocDoc world-wide. …There is a global shortage of doctors, and it’s difficult to book a doctor anywhere in the world.”

In fact, despite Massoumi’s repeated emphasis of the company’s US focus during our interview, ZocDoc currently lists job openings for general managers in Australia, Brazil, Canada, China, France, Germany, India, Italy, Japan, Mexico, and the UK.

ZocDoc’s UK listing, for example, calls for applicants to “define and execute strategies to develop our entry into the UK market.” Requirements for that particular role include a “strong desire to improve access to healthcare in the UK.” ZocDoc has also supported multiple languages since 2012.